Evaluating malaria prevalence and land cover across varying transmission intensity in Tanzania using a cross-sectional survey of school-aged children

BACKGROUND: Transmission of malaria in sub-Saharan Africa has become increasingly stratified following decades of malaria control interventions. The extent to which environmental and land cover risk factors for malaria may differ across distinct strata of transmission intensity is not well known and could provide actionable targets to maximize the success of malaria control efforts. METHODS: This study used cross-sectional malaria survey data from a nationally representative cohort of school-aged children in Tanzania, and satellite-derived measures for environmental features and land cover. Hierarchical logistic regression models were applied to evaluate associations between land cover and malaria prevalence within three distinct strata of transmission intensity: low and unstable, moderate and seasonal, and high and perennial. RESULTS: In areas with low malaria transmission, each 10-percentage point increase in cropland cover was associated with an increase in malaria prevalence odds of 2.44 (95% UI: 1.27, 5.11). However, at moderate and higher levels of transmission intensity, no association between cropland cover and malaria prevalence was detected. Small associations were observed between greater grassland cover and greater malaria prevalence in high intensity settings (prevalence odds ratio (POR): 1.10, 95% UI: 1.00, 1.21), and between greater forest cover and reduced malaria prevalence in low transmission areas (POR: 0.74, 95% UI: 0.51, 1.03), however the uncertainty intervals of both estimates included the null. CONCLUSIONS: The intensity of malaria transmission appears to modify relationships between land cover and malaria prevalence among school-aged children in Tanzania. In particular, greater cropland cover was positively associated with increased malaria prevalence in areas with low transmission intensity and presents an actionable target for environmental vector control interventions to complement current malaria control activities. As areas are nearing malaria elimination, it is important to re-evaluate environmental risk factors and employ appropriate interventions to effectively address low-level malaria transmission

Some Physical And Mechanical Properties Of Uapaca Kirkiana, A Lesser-Known Timber Species From Tanzania

This study was carried out to determine some physical and mechanical properties of Uapaca kirkiana a lesser known timber species growing in public land near Iyondo Catchment Forest Reserve, Kilombero District, Morogoro, Tanzania. A total of 3 trees were used in the study. Preparation of test samples and laboratory procedure to determine some physical and mechanical properties followed standard methods. Analysis of variance was used to determine the variation between and within trees and regression analysis was used to determine relationship between wood basic density and mechanical properties. The results showed that Uapaca kirkiana has whitish sapwood and dark brown heartwood, with a mean basic density of 518.14 kg/m3. The properties of Uapaca kirkiana were as follows: modulus of elasticity (7185.69 N/mm2), modulus of rupture (59.7 N/mm2), work to maximum load (0.06 mmN/mm3), total work to failure (0.07 mmN/mm3), shear strength parallel to the grain (11.86 N/mm2), compression strength parallel to the grain (34.4 N/mm2) and cleavage strength (20.21 N/mm width). On axial direction, the modulus of elasticity, total work to failure, compression strength parallel to grain and cleavage strength were directly proportional to its basic density while modulus of rupture, work to maximum load and shear strength parallel to the grain were inversely proportional implying that Uapaca kirkiana is suitable for activities, which require high modulus of elasticity, total work to failure, compression strength parallel to the grain and cleavage strength. On radial direction modulus of elasticity, modulus of rupture, work to maximum load, compression parallel to the grain and cleavage strength were directly proportional to basic density while shear parallel to the grain was inversely proportional to basic density. Compared to Khaya anthotheca, the timber species found in the same location and market; it was found that the timber of Uapaca kirkiana had modulus of rupture and compression parallel to the grain far lower than those of Khaya anthotheca, while the work to maximum load, total work to failure, shear strength parallel to grain and modulus of elasticity were almost the same. Due to the similarity in some of their physical and mechanical properties, the wood of Uapaca kirkiana may berecommended to substitute Khaya anthotheca in wood works that require medium density wood like in decoration where colour is considered an important aspect for appearance and in cabinet, panel and furniture making though it is not adequate in high-class strength joinery. TJFNC Vol. 76 2007: pp. 94-10

Potentials of lesser known and lesser utilized indigenous agroforestry timbers in Kilosa District, Morogoro Tanzania

International Journal of Education and Research 2015: Vol 3(12)The paper presents baseline results of gathered important information for inference in establishing optimal production and utilization of Lesser-known (LK) and Lesser-utilized (LU) indigenous agroforestry timber species (IAGTS) in improving incomes of rural communities in Kilosa District. The main key questions were: what are the characteristics of the sites for establishing LK and LU IAGTS; who are the main actors in establishing LK and LU IAGTS; what are LK and LU IAGTS and other species for establishment in the study area and what are the strengths, weaknesses, opportunities and threats for establishing LK and LU IAGTS in the study area. Data collection was participatory, involving key stakeholders, participants’ observations and literature surveys. A total of eight villages were identified as potential sites for nursery establishment with seven main actors’ mostly local communities engaged in tree planting activities under associations. Five priority LK and LU IAGTS were identified and selected for nursery establishment. These were: Lonchocarpus capassa (Mfumbili), Sclerocarya birrea (Mng’ongo), Vitex doniana (Mfudu), Pseudolachnostylis maprouneifolia (Msolo) and Combretum zeyheri (Mlama mweupe). The strengths and opportunities favouring the establishment of LK and LU IAGTS nurseries were identified, with a few weaknesses and threats which needed to be worked upon

Vitex doniana sweet: A potential lesser-known and lesser utilized agro-forestry timber species in Kilosa District, Morogoro Tanzania

International Journal of Contemporary Applied Sciences 2015: Vol. 3, (1)Tanzania is classified as among the 15 poorest nations in the world, with an estimated per capita income of less than US$ 190. Over 80 % of the country’s population of about 46 million lives in rural areas. Living in such a poor country, the people have few feasible alternatives to exploiting the forest resources resulting in high deforestation rate estimated at 2 % annually. Nevertheless, many timber species are still not known to users, resulting into over-exploitation of few well-known timber species. The timber stakeholders need alternatives and the national economies need better ways to derive value from the remaining forests in order to maintain their many useful but under-valued functions. One option is to optimize the production and utilization of lesser-known and lesser-utilized indigenous timber species which are potential for agro-forestry. One of such species is Vitex doniana Sweet which belongs to the family Lamiaceae. It is a deciduous tree with medium-growth rate and is widespread in tropical Africa. V. doniana is being threatened by habitat loss. This paper attempts to analyze some potentials of V. doniana as an agroforestry tree. The studied properties were: i) Physical – Tree dimension, form and quality, wood colour, texture, workability and basic density ii) Strength - Static bending, compression, shear and cleavage and iii) Anatomical - growth rings, vessels arrangement, density and size, gum deposits, parenchyma and ray tissue. The average physical properties are as follows: The sapwood is white while the heartwood is pale greyish-brown and basic density is 650 kg m-3. The strength properties are: Modulus of elasticity (11,100 N mm-2), Modulus of rapture (98.14 N mm-2), Work to maximum load before failure (0.131 mm N mm-3) and Total Work (0.239 mm N mm-3). The impact bending strength was 1.02 m, Hardness (4,580 N), Compression parallel to the grain (52.5 N mm-2), Shear parallel to the grain (15.6 N mm-2) and Cleavage (9.0 N mm-1). This species depicts well-marked growth rings and therefore ring-porous, meaning a course textured timber. The average strength properties are closely comparable to those of Tectona grandis (Teak). Also, Vitex doniana has other multiple benefits: bears edible fruits, suitable as ornamental tree and windbreak, shade and its leaves are useful as vegetable and as well as for soil improvement

Estimating malaria burden among pregnant women using data from antenatal care centres in Tanzania: a population-based study

BACKGROUND: More timely estimates of malaria prevalence are needed to inform optimal control strategies and measure progress. Since 2014, Tanzania has implemented nationwide malaria screening for all pregnant women within the antenatal care system. We aimed to compare malaria test results during antenatal care to two population-based prevalence surveys in Tanzanian children aged 6-59 months to examine their potential in measuring malaria trends and progress towards elimination. METHODS: Malaria test results from pregnant women screened at their first antenatal care visits at health-care facilities (private and public) in all 184 districts of Tanzania between Jan 1, 2014, and Dec 31, 2017, were collected from the Health Management Information Systems and District Health Information System 2. We excluded facilities with no recorded antenatal care attendees during the time period. We standardised results to account for testing uptake and weighted them by the timing of two population-based surveys of childhood malaria prevalence done in 2015-16 (Demographic and Health Survey) and 2017 (Malaria Indicator Survey). We assessed regional-level correlation using Spearman's coefficient and assessed the consistency of monthly district-level prevalence ranking using Kendall's correlation coefficient. FINDINGS: Correlation between malaria prevalence at antenatal care and among children younger than 5 years was high (r≥0·83 for both surveys), although declines in prevalence at antenatal care were generally smaller than among children. Consistent heterogeneity (p<0·05) in antenatal care prevalence at the district level was evident in all but one region (Kilimanjaro). Data from antenatal care showed declining prevalence in three regions (Arusha, Kilimanjaro, and Manyara) where surveys estimated zero prevalence. INTERPRETATION: Routine antenatal care-based screening can be used to assess heterogeneity in transmission at finer resolution than population-based surveys, and provides sample sizes powered to detect changes, notably in areas of low transmission where surveys lack power. Declines in prevalence at antenatal care might lag behind those among children, highlighting the value of monitoring burden and continuing prevention efforts among pregnant women as transmission declines. The pregnancy-specific benefits and cost-effectiveness of antenatal care-based screening remain to be assessed. FUNDING: None

Modelling the incremental benefit of introducing malaria screening strategies to antenatal care in Africa

Plasmodium falciparum in pregnancy is a major cause of adverse pregnancy outcomes. We combine performance estimates of standard rapid diagnostic tests (RDT) from trials of intermittent screening and treatment in pregnancy (ISTp) with modelling to assess whether screening at antenatal visits improves upon current intermittent preventative therapy with sulphadoxine-pyrimethamine (IPTp-SP). We estimate that RDTs in primigravidae at first antenatal visit are substantially more sensitive than in non-pregnant adults (OR=17.2, 95% Cr.I. 13.8-21.6), and that sensitivity declines in subsequent visits and with gravidity, likely driven by declining susceptibility to placental infection. Monthly ISTp with standard RDTs, even with highly effective drugs, is not superior to monthly IPTp-SP. However, a hybrid strategy, recently adopted in Tanzania, combining testing and treatment at first visit with IPTp-SP may offer benefit, especially in areas with high-grade SP resistance. Screening and treatment in the first trimester, when IPTp-SP is contraindicated, could substantially improve pregnancy outcomes